As a House Race Tightens in Kansas, Republicans See a Possible Warning Sign

WICHITA, Kan. — Congressional Republicans knew next year’s election could prove difficult, as the first midterm campaigns for the party controlling the White House often are. But not until a few days ago would they have believed that their immediate challenge would be hanging onto a House seat they have controlled for over two decades, in a district that President Trump carried by 27 points and that just happens to be home to that most nefarious of liberal boogeyman: Koch Industries.

Yet that is exactly what has happened since last week, when the House Republican campaign committee received a poll showing its candidate here in south-central Kansas winning by only single digits. Rushing to save the seat vacated by Mike Pompeo, now the C.I.A. director, before a special election on Tuesday, Republicans blasted out automated phone calls from Mr. Trump, hastily crafted an ad attacking the Democratic candidate on abortion, and dispatched Senator Ted Cruz of Texas for an 11th-hour rally on Monday afternoon with their own nominee.

“Our enemy right now is complacency,” Mr. Cruz told a lightly filled airplane hangar, picking up where he left off from his own presidential campaign last year. But this time, he was on a Republican rescue mission for Ron Estes, a House candidate.

As Kansas’ state treasurer, the mild-mannered Mr. Estes, an engineer by trade, has twice been on a statewide ballot. And he was initially not expected to have any difficulty keeping the seat in Republican hands in the race against a political newcomer, James Thompson, a Wichita civil rights lawyer.

But with national Republicans focused chiefly on another surprisingly competitive special House election in Georgia, and Mr. Thompson, the Democratic nominee, lashing Mr. Estes for his ties to the deeply unpopular Gov. Sam Brownback, the race has appeared to tighten. Or at least become closer than Republicans would prefer at a moment when liberals are eager to register their fury toward Mr. Trump. Additionally, the election is being held on the second Tuesday in April of an odd year, making turnout unpredictable.

“Most years it’s not very important, but tomorrow, April 11 is very important,” Mr. Estes said in his own remarks on Monday, which were considerably more clipped than those of Mr. Cruz.

The late scramble in Kansas may prove the political equivalent of taking out an insurance policy, as some national Republicans privately put it. But the spectacle of Mr. Cruz and a senior national Chamber of Commerce official descending on Wichita’s airport just hours before Election Day to prop up Mr. Estes evoked panic more than premium-paying.

“My being here is indicative that I think that this race matters,” Mr. Cruz told reporters before the rally as he stood with Mr. Estes and Rob Engstrom, political director for the Chamber of Commerce, barely deflecting a question about whether Republicans were worried about the race.

That this contest and the race to fill the reliably Republican Georgia seat vacated by Tom Price, now the health secretary, require any substantial intervention is an ominous sign for Republicans. Should the Georgia race require a June runoff, national Republican groups could find themselves spending over $7 million to protect territory they have rarely thought of when it comes to House races. And that is to say nothing of the open House seat in Montana, formerly held by the interior secretary, Ryan Zinke, which has already been supplied with outside Republican funding and could demand more before it is over on May 25.

Taken together, the spending amounts to a flashing red warning sign for Republicans on the ballot next year.

“If you’re an incumbent Republican member of Congress, this is an indication you need to be executing the fundamentals back home,” said Ken Spain, a Republican strategist who worked for the House Republican campaign committee when it went on the offensive in President Barack Obama’s first midterm.

Republicans may have been roused in enough time to elect Mr. Estes. A “super PAC” aligned with the House Republican leadership spent $50,000 on a late wave of live get-out-the-vote calls to Republican voters. A Koch-affiliated group has also conducted phone banks aimed at mobilization, albeit not for Mr. Estes specifically (notably, there is also a Libertarian on the ballot).

And the National Republican Congressional Committee last week began airing a commercial that accuses Mr. Thompson of supporting abortion for gender selection, a charge he denies and chalks up to desperation on the part of his opponent. But in a region where opposition to abortion is central to the sort of conservative political activists who are likely to show up for a special election, it redirected the campaign debate as early voting was underway.

The Fourth Congressional District is anchored in Wichita — an aviation manufacturing hub and Kansas’ largest city — but also includes 16 heavily conservative farm counties. So while there is Democratic strength because of the urban mix of college campuses, organized labor and racial minorities, this is unmistakably red America.

While plainly benefiting from the backlash on the left against Mr. Trump, Mr. Thompson recognizes he needs the president’s backers to win here. So he is trying to swap out Mr. Trump as the preferred villain for Mr. Brownback, whose approval ratings have plummeted in the wake of his cuts to education spending.

“There’s still a lot of people here that support President Trump,” Mr. Thompson said in an interview as he mingled with lunch customers on Monday at a Wichita bar and grill, adding, “It’s more a referendum on Brownback.”

Mr. Estes and a raft of his surrogates representing a handful of conservative constituencies have assailed Mr. Thompson as a tool of a liberal national party. The Democrat, a supporter of Bernie Sanders in last year’s presidential primary, cast himself as a moderate.

“I got tired of seeing both sides arguing all of the time, not doing their job,” Mr. Thompson said. “People are tired of the extreme.”

But he could have used more assistance from the national Democrats to whom Republicans are so determined to link him. While he enjoyed a late infusion of nearly $150,000 from Daily Kos, a liberal blog, Mr. Thompson received little help from the House Democratic campaign arm beyond a late wave of turnout calls.

“They’ve been concentrating on the Georgia race,” he said matter-of-factly.

“We knew from the beginning that it was going to be hard to get national attention, but we knew that we had a chance,” he said.

A version of this article appears in print on , on Page A19 of the New York edition with the headline: Special House Election in Kansas Brings the G.O.P. a Surprise: A Competitive Race. Order Reprints | Today’s Paper | Subscribe